Cyanobacteria such as Spirulina contain phycocyanin and have been used as functional materials such as health foods, and food dyes.
As preparation methods for phycocyanin from cyanobacteria, there have been known methods disclosed in Patent Literatures 1 and 2.
The methods disclosed in Patent Literatures 1 and 2 involve using calcium phosphate as a flocculant. In the methods, however, filtration rates are very low, and purity is insufficient. Centrifugation may be carried out to remove impurities, but in the cases, the impurities cannot be removed satisfactorily.
A phycocyanin-containing solution after separation contains a high concentration of impurities and causes clogging. Therefore, a step of solid-liquid separation by filtration is difficult to be performed, and a step of sterilization using a filter cannot be integrated thereinto.
Phycocyanin is heat-labile and hence cannot be sterilized by heating or using a filter during the steps. Therefore, it has been necessary to immediately dry a product and then to sterilize the dried product.